METHOD OF MANUFACTURING HIGH-STRENGTH HEAT-RESISTANT THREADS FROM AROMATIC COPOLYAMIDE HAVING HETEROCYCLES IN THE CHAIN

摘要

FIELD: polymer production.;SUBSTANCE: invention relates to technology of manufacturing high-strength heat-resistant threads from aromatic copolyamide having heterocycles in the chain, in particular copolyamidobenzimidazole, and can be used to reinforce plastics, in manufacture of technical rubber articles, fiber optics cables, and other special-destination articles. Method comprises dissolving 5(6)-amino-2-(4-aminophenyl)benzimidazole in amide solvent in presence of LiCl or CaCl₂ at 18-24°C. p-Phenylenediamine is then added during cooling of resulting solution to 0-15°C and two-step low-temperature polycondensation is effected by introducing 80-90 mol % terephthaloyl chloride until formation of oligomer, after which follows filtration of oligomer and reaction is continued to achieve required viscosity of copolymer. Molding is effected at 18-24°C. In second embodiment of industry, diamines are dissolved simultaneously, resulting polycondensation solution is heated to 25-35°C, and molding in water-organic bath is carried out at the same temperature. After plasticizing stretching, rinsing, and drying, thread is subjected to heat treatment at 350-360°C for 0.5 h and then to thermal stretching by 1.0-1.5% at 370-410°C.;EFFECT: improved mechanical properties of threads.;9 cl, 2 tbl, 34 ex